Binocular focusing mechanism having indexing detent



Aug. 16,1966 R. w. DOWLING ET AL 3,

BI NOCULAR FOCUSING MECHANISM HAVING INDEXING DETENT Original Filed Aug.31 1961 v Sheets-Sheet 1 y IO INVENTORS ROBERT WHITTLE DOWLING LORENZODQIRICCIO ALBERT GOLDHAMMER ATTORNEYS Aug. 16,1966 R. w. DOWLING ET AL3,266,367

BINOCULAR FOCUSING MECHANISM HAVING INDEXING DETENT Original Filed Aug.51 1961 7 Sheets-Sheet 2 Will" INVENTORS ROBERT WHITTLE DOWLING LORENZODEIRICCIO ALBERT GOLDHAMMER AT RNEYS Aug. 16, 1966 I w, DOWUNG ET AL3,266,367

BINOCULAR FOCUSING MECHANISM HAVING INDEXING DETENT INVENTORS ROBERTWHITT-LE DOWLING LORENZO DelRICCIO BY ALBERT GOLDHAMMER W mmeh, m1; 1 Q$14M AT ORN EYS Aug. 16, 1966 R. w. DOWLING ET AL 3,2

' BINOCULAR FOCUSING MECHANISM HAVING INDEXING DETENT Original FiledAug. 51 1961 7 Sheets-Sheet 4 FIG.

m m S C 5 R o M m T D N mm d ET. QQRO W T W m/W T M FM d4, Wurfi Aug.16, 1966 R. w. DOWLING E AL 3,266,367

BINOCULAR FOCUSING MECHANISM HAVING INDEXING DETENT Original Filed Aug.51 1961 '7 Sheets-Sheet 5 FIG. 13

INVENTORS ROBERT WHITTLE DOWLING LORENZO DelRlCCIO BY LBER GOLDHA MERMFMA, L Jun ATTORa EY Aug. 16, 1966 R. w. DOWLING E AL 3,266,357

' BINOCULAR FOCUSING MECHANISM HAVING INDEXING DETENT Original FiledAug. 51. 1961' '7 Sheets-Sheet 7 INVENTORS R0 T HITTLE DOWLING L E ODelRl 0 am, am ahffimzfi :ggggm United States Patent 3,266,367 BINOGULARFOCUSING MECHANISM HAVING INDEXING DETENT Robert W. Dowiing, New York,N.Y., Lorenzo del Riccio, Los Angeles, Calif., and Albert Goldharnmer,Nussdorl, Baden (Bodensee), Germany, assignors to D and D Company, Inc,New York, N.Y., a corporation of Delaware Original application Aug. 31,1961, Ser. No. 135,182. Divided and this application Aug. 16, 1963, Ser.No.

4 Claims. (CI. 8834) This is a division of application Serial No.135,182, filed August 31, 1961.

This invention relates to binocular telescopes and specifically toimprovements in the focusing mechanisms thereof.

The invention herein illustrated and described is incorporated in abinocular having two flat box-like lens casings mounted for transverseslidable movement upon a connecting central bridge. The lens casings aremovable from a closed position wherein they completely envelop thecentral bridge to positions where the lens casings are movedtransversely outwardly to provide interpupillary distance accommodation.The binocular thus presents a fiat oblong shape which is easily carriedor handled and may, when closed, be conveniently slipped into pocket orpurse without the necessity of having a specially molded carrying case.

A binocular of the type described finds its greatest use as a sportsglass or theater glass. Consequently, it is advantageous to make theobjective lenses of the bin ocular of a generally rectangular outlineand of greater width than height. This arrangement permits of arelatively wide or panoramic field of view while sacrificing only thefield of view in a vertical direction, in which direction it is notgenerally needed for theater or sports use.

According to the invention novel means are provided for mounting theoptics of binocular lens systems and for providing movement of portionsof the lens systems to effect focusing for each eye individually or inunison. One of the reflecting members of each binocular optical systemis movable parallel to the optical axes to vary the distance which thelight travels within a lens system. Thus, the compact shape of thebinocular is unaltered by focusing adjustments since these occur bymoving parts internally mounted within each lens casing.

Means are also provided in cooperation with the focusing mechanism ofthe invention to permit the user of the binocular to register, by adetent device, the position of long range focus adjustment. If,therefore, the owner of the binocular wishes to readjust the focus forshort range viewing, he can return to the long range focus position byturning the focusing knob until he noties an appreciable resistanace,which is the registered detent position.

In combination with the foregoing are provided certain novel binocularconstructions which form the subject matters of co-pending applicationsone of which concerns the arrangement of the optical elements within abox-like lens casing in a mannner such that the overall height of thebinocular may be reduced to a minimum. This is effected by inclining theplanes of the light path through a casing with respect to a horizontalaxis or axis of symmetry of the casing. In addition to reducing theheight of the casing, a further advantage of the arrangement is that thebinocular may be declined somewhat when in use, which makes thebinocular easier and less tiresome to hold.

A further aspect of the presently disclosed binocular is the provisionof slidable lens shutters for each of the lenses of a lens system, whichshutters are automatically ice extended over the lens apertures when thecasings are moved to closed positions. The shutters automaticallyuncover the lens apertures upon movement of the lens casings to aminimum interpupillary distance.

Optical filters herein disclosed may be selectively brought into thelight path in order to make possible or more convenient the viewing ofcertain events under conditions of extreme brightness or glare.

In the following description reference is made by way of non-limitingexample to one form of construction of a binocular devised in accordancewith the invention, and illustrated in the accompanying drawings inwhich:

FIG. 1 is a perspective view showing the binocular of the presentinvention with the lens casings thereof in their closed positions andwith the lens shutters shown covering the ocular lenses thereof;

FIG. 2 is a view similar to FIG. 1 showing the lens casings in theiropen positions for interpupillary distance accommodation;

FIG. 3 is a perspective view showing the arrangement of the opticalelements within a single lens system;

FIG. 4 illustrates the manner in which the optical elements of a lenssystem are tilted respective of a horizontal axis through a lens casing;

FIG. 5 is a plan view of the binocular of the FIG. 1 showingparticularly elements of the lens casing and the intermediate centralbridge permitting their relative slidable movement, and also elements ofthe lens cover actuation mechanism;

FIG. 6 is a side elevation of the binocular illustrated in FIG. 5;

FIG. 7 is a cross-sectional view taken substantially along line 77 ofFIG. 5;

FIG. 8 is a cross-sectional view taken substantially along line 88 ofFIG. 5;

FIG. 9 is a cross-sectional view taken substantially along line 9-9 ofFIG. 5;

FIG. 10 is a detailed view in the direction indicated by arrows 10-10 ofFIG. 5, disclosing the actuation mechanism for a lens filter;

FIG. 11 is a view similar to FIG. 10 with the lens filter in position tocover an ocular lens;

FIG. 12 is a cross-sectional view taken substantially along line 12-12of FIG. 11;

FIG. 13 is a transverse cross section view taken substantially alongline 13-43 of FIG. 5, illustrating various interrelated portions of thefocuing mechanism within the central bridge member;

FIG. 14 is a vertical longitudinal cross section of the central bridgenormal to the optical axes taken along line 1414 of FIG. 13;

FIG. 15 is a horizontal longitudinal cross section of the central bridgetaken along line 15-15 of FIG. 13;

FIG. 16 is a vertical cross section illustrating the focusing knob andelements of the focus detent mechanism taken along line 1616 of FIG. 15;

FIG. 17 is an exploded view of the elements illustrated in FIG. 16;

FIG. 18 is a section view taken along line 1818 of FIG. 16.

Referring now to the drawing and specifically to FIGS. 1 and 2, abinocular 10 has been illustrated which incorporates the severalfeatures of the invention. The binocular 10 has lens casings 11, 12which are mounted for slidable transverse movement upon aninterconnecting central bridge support 13. The degree of such movementfor individual interpupillary distance accommodation may be recorded bynoting the position of the easings relative to vertical indicia on thesupport (FIG. 5). The binocular has ocular lens apertures 15 formedwithin each casing and ocular lens units 16.

The central bridge 13 comprises an elongate member 3 having symmetricalarms 18, 19 (FIGS. 5 and 6) which extend into each of the lens casings11 and 12. The arms 18, 19 are each of U-shaped cross section to presentupper and lower portions thereof which are outside of the field of sightwithin a casing. Each casing is boxlike in form, including a main frameor housing structure 42 having a generally hollow interior for mountingthe various optical elements of a lens system, as will be describedpresently. The housing 42 mounts guide rails 20 which slidably receivethe upper and lower portions of the U-shaped arms 18, 19 for permittingthe lens casings to be moved outwardly along the central support.

Lens Shutters Each of the arms 18, 19 is attached by screws to cambrackets 21, each of which has a recess bounded by surfaces 22, 23 and24. The lens casings each mount a telescoping actuating arm 26 rotatableabout pivot 27. The ends of the arms 26 are pivotally connected at 28and 29 respectively to lens shutters 30, 31 which are slidable withinrecesses 32, 33 within the lens casings. The shutters are plates whichmay be stamped to have embossed thereon a vertical segment whichsimulates louvered construction. The lens shutters 30, 31 have U- shapedupper and lower edges 30a, 3111 respectively which in effect formgrooves for receiving ridges 34 forming part of the lens casingstructure (see FIG. 7). The ridges 34 and U-shaped sections 30a, 31a ofthe lens shutters comprise a means for guiding the lens shutters duringtheir slidable movement within the recesses 32 and 33.

The arms 26 each mount a pin 26' which cooperates with the cam bracket21 to rotate the arms 26 about pivot points 27, thus causing slidingmovement of the lens shutters 30, 31. If, for example, the arms 18 wereto move into the lens casing 11, the pin 26' would first contact surface24 of the cam bracket 21 attached to arm 18. Further movement of the arm18 into the casing 11 would cause counter-clockwise rotation of the lensshutter actuating arm 26 about pivot 27. The arms 26 would then movesimultaeously each of the lens covers 30, 31 across the related lensapertures in the direction of the arrows. During this entire movement,the pin 26 is in contact with the surface 24 of the cam bracket 21 buttends to move up into the slot to the position illustrated in the righthand portion of FIG. 5 with respect to lens casing 12.

When a lens casing is moved outwardly along the central support, thesurface 23 of each cam bracket 21 hooks against its respective drive pin26' by reaction of the pin against surface 23 of the cam, to pull thedrive pin and to cause reverse rotation of the arms 26 for effectinguncovering of the lens apertures. The movement of the lens shutterstherefore will begin immediately upon outward movement of the lenscasings and continues to a position of minimum interpupillary distanceaccommodation at which point lens covers are completely shifted awayfrom the lens apertures. The construction of the cam bracket 21 and thelocation and movement of the pin 26' is such that when the shutters arecompletely withdrawn from the lens apertures, the pin 26 will move outof the slotted portion of the bracket 21 and slide against the straightsurface 22 of the cam bracket, thereby effectively uncoupling thebracket from the pin. Upon return movement of the lens casings topositions approximating a minimum interpupillary distance, the surfaces24 of each cam bracket will engage the respective pins 26' and theshutters will be moved over the lens apertures.

In order to assure equilateral displacement of each of the lens casings11 and 12 with respect to the central bridge each of the casings mountsa rack strip 36 whose teeth mesh with a freely rotatable pinion 37mounted to the central support (FIGS. 5, 13, 14). Thus, when the lenscasings are displaced from their closed positions,

the displacement of one casing will be equal to the displacement of theother. It will be understood that the central support 13 includes stops(not shown) which abut portions of the lens casings and which terminateor limit the outward movement of the casings.

Lens optical filters According to another feature of the presentinvention, optical filters are provided which may be selectively movedacross the optical axis in each casing to protect against glare, strongsunlight, etc. With reference particularly to FIGS. 7, 8 and 12, afilter frame 35 having front and side portions 35a, 35b is providedwhich holds an optical filter 38. The frame 35 is slidable in adirection normal to the optical axis and is guided in such movement byboth a rearward tang 356 which slidably engages the edge of a groove 40in the ocular lens mount and the walls of a slot 40a formed in the outerportion of the ocular lens unit 16. A button receptacle 41 is slidablein a vertical groove 42 in the housing structure 42. A pin 41 (FIG. 7)extends from the button receptacle 41 into a slot 43 formed in the side3512 of the filter frame 35. This arrangement permits the filter frame15 to follow a path normal to the inclined optical axis and the buttonreceptacle 41 to move in a true vertical direction. The outer end of thebutton receptacle is connected to a semicircular disc 45 which mounts apin 46. Outwardly of the disc 45 and adjacent thereto is a plate 4'7attached to the housing structure 42 by means of screws 48. The plate 47has a slot 47' which receives the pin 4-6 and consequently, when thebutton receptacle 41 is moved vertically, the disc 45 will be forced topivot vithin the slot 47' of the plate 47.

An actuating button 44 is mounted within the receptacle 41 and isnormally urged outward by a spring 41" therein. The button protrudesthrough a vertical slot 47 in the plate 47 and through a similar alignedslot 39 in an outer cover plate 39. When the casings are in closedclosely adjacent positions, however, the button 44 will be urged againstthe spring and into the body of the receptacle 41.

The semicircular disc 45 has a rounded inner edge portion which pressesagainst a rounded leaf spring number 49. The construction andrelationship of the spring 49 and disc 45 is such that the disc willurge the receptacle 41 into one or the other of its end positions andwill act as an over-center resilient actuator upon release of the buttonin an intermediate position. An additional valuable function of the disc45 is to slide intermediate the housing structure 42 and the outerplates 47 and 39, each of which is grooved or slotted to provide passagefor the button 41. During such sliding movement of the disc 45, therespective groove and slots will be covered by the disc against thepossible ingress of dirt or other foreign materials into the casing.

Binocular lens system With reference to FIGS. 3, 4, 8, 9 and 12 it willbe observed that the light path proceeds through the objective lens 58and is reflected by the mirror 51 at right angles to its initialdirection. A prism 52 then receives the light, reflects the lightforwardly at a right angle to a first reflecting surface 53a of thesecond prism 53. The surface 53a reflects the beam of light upwardly tobe reflected again rearwardly by a second surface 5311, from which thelight proceeds through the ocular lens unit 16.

It will be observed with reference specifically to FIG. 4 that each ofthe optical units are arranged to cause the planes of the light path tobe inclined with respect to a reference plane or axis of symmetrypassing intermediate the top and bottom walls of a lens casing, whoseoutline has been indicated in solid line. The objective and ocular lensunits are however, arranged substantially along the axis of symmetry ofthe casing, consequently, the height of the casing is less than if thelens elements were mounted in the conventional manner (as indicated bythe dotted outline) so that the planes of the light path are parallel tothe top and bottom of a casing.

A further advantage to the disclosed arrangement is that duringtheviewing of an event, the binocular may be downwardly inclined (solidline position of FIG. 4) which position is more restful to the arms ofthe user.

With reference to FIG. 3, it may be observed that the prism 53 ismovable in a direction parallel to the light path as indicated by thearrow. As will be described presently with specific reference tostructural details, the prism 53 is movable in order to provide focusingadjustment of each lens system. When the prism 53 is moved, the distancewhich the light must travel between ocular and objective lenses isincreased or diminished to vary the focus.

The lens 53 need be moved only one-half the distance which wouldordinarily be necessary for movement of an ocular lens unit, forexample, in systems where the ocular lens is movable to providefocusing. Consequently, less focusing adjustment is required and thecasing may be better sealed against the ingress of dust or other foreignparticles than would be possible where the ocular lens unit is movable.

Proceeding now to the structural details of the aforementioned lenssystem, we refer specifically to FIGS. 79 and 14 and 15. With referenceto FIGS. 7-9, the objective lens unit 50 is inclined slightly with itsupper edge toward the rear of the casing and is held securely within alens mount 55 secured to frame 42. Light passes through the objectivelens to the mirror 51 and from the mirror to the prism 52 (FIGS. 8 and12) and therefrom in a forward direction to the movable prism 53. Theprism 53 reflects the received light both upwardly and rearwardlythrough the ocular lens unit 16. Prism 53 is attached by cement to, oris made integral with a mount 58. Attached to the mount 58 is a shaft 59which is slidable within a bore 60 formed within the frame 42. The endof shaft 59 is tapped to receive a threaded screw 61. Between the headof the screw and an abutment shoulder 62 defined by the frame 42, ahelical spring 65 'is disposed tending to bias the shaft 59 toward theforward or objective lens portion of the frame 42. The prism 53 may beshifted toward the rear of the casing by means of a cam 63 (FIGS. 7, 14and 15 whose outer periphery is in the form of an Archimedes spiral. Thecam 63 may be rotated by a rectangular-shaped shaft 64 and when suchrotation takes place, the surface of the cam will thrust the mount 58and prism 53 toward the ocular lens 16. The spring 65 provides a returnaction.

Focus adjustment With reference to FIG. 15, an externally operablefocusing wheel 66 is connected to a drive shaft 67 by means of an oblongslot 69 (FIG. 16) and the screw 70. The drive shaft 67 therefore rotateswhenever the focusing wheel 66 is rotated. At its lower end, the shaft67 comprises a bevel gear 71 which meshes with a second bevel gear 72rotatable within a clutch housing 68. The housing is fixed to thecentral bridge 13 and the gear 72 has attached thereto a member 72forming part of a clutch generally designated by numeral 74. Radialserrations 72" normally engage similar serrations 73' on a movablemember 73 of the clutch. The movable member 73 is biased against themember 72' by a spring 75. The spring 75 is seated in a counterbore in ajournal 76 which is retained by means of the screws 77.

The members 72, 73 are hollow to receive the hooked ends 64' of tworectangular-shaped drive rods 64. Opposite ends of the rods 64 extendinto the frame or housing 42 of each casing, and as shown in the righthand portion of FIG. 15 connect with one of the earns 63. The latter aremounted by the screws 79 to hubs 80 and each of the rods 64 is slidablewith respect to its hub such :that when the casings are in their closedpositions, the

ends of the rods extend for a distance beyond their connection with thehubs 80. The hooked ends 64' of the rods 64 within the clutch elements72a and 73, prevent removal of the rods therefrom by frictional forceswhen the lens casings are moved outwardly relative to the central bridge13. A tubular member 78 is located Within the clutch 74 and acts as astop against which ends 64' of the rods 64 abut when the lens casingsare moved to closed positions. The free ends of the rod 64 opposite tothe inner hooked ends 64' extend from the hubs a sufiicient distance toremain in engagement with the hubs in all positions of the lens casings.

The invention also provides for individual focus adjustment of therespective lens systems independently of each other. By operation of thefocusing adjustment just described with respect to FIG. 15, both lenssystems are focused in unison through the clutch 74. When this has beenaccomplished to the satisfaction of the user, he may uncouple theleft-hand (as viewed in FIG. 15) focus adjustment drive rod 64 andcontinue to operate the focus wheel 66 to adjust the right hand prism 53independently. The means for accomplishing this result is best seen inFIGS. 13 and 14 and comprises an externally accessible button 81 whichwhen pressed, rotates a bell crank 82 about its pivot 83. The end of thebell crank 82 is connected by tangs 85 to the element 73. Element 73 itwill be remembered is spring-biased into meshing engageemnt with thefixed clutch portion 72, but when the button 81 is depressed, the bellcrank 82 will separate the element 73 from the portion 72 and rotationof the focus wheel 66 effects only actuation of the right hand prismshown in FIG. 15.

As best seen in FIGS. 15, 16 and 17, a mechanism is provided inassociation with the disclosed focusing adjustment, to permit the userof the binocular to record or indicate for later reference the precisefocus setting which for him is the correct long distance adjustment. Forthis purpose, a detent gear having a stop 90' is freely rotatable aboutthe drive shaft 67 and has attached to its upper surface a disc 91. Thelatter defines at one point in its periphery a detent or recess 92. Im-

mediately above the disc 91 and freely rotatable with respect to it andthe detent gear 90, is a follower disc 93 carrying a stop arm 94. Thefocus wheel 66 on its underside defines a rectangular recess 95. Mountedwithin the recess 95 is a slide 96 which has a slot 97 to permit lateralmovement of the slide relative to drive shaft 67. The slide 96 is biasedtoward the left as shown in FIGS. 16 and 17 by a spring 98 lying betweenthe shaft 67 and an integral lug 99 forming a portion of the slide 96.The slide 96 at its edge opposite the lug 99 has a downturned lug ornose 100. The relationship of the component parts is such that the nose100 is adapted to ride along the periphery of the disc 91 and beingurged toward the left by the spring 98, the nose 101 will drop into thedetent 92 when the focusing wheel moves the slide in a position adjacentto the detent. Thereafter, the rotation of the focus wheel 66 will alsorotate the detent gear 90 unless the detent gear is prevented fromrotation.

The detent gear may be selectively prevented from rotation with shaft 67by engagement with the teeth of a registering lever 101. The lever 101has a projecting tab 102 which extends externally of the central bridge13 immediately below the focus wheel. When the user of the binocular hasobtained his own individual long distance focus adjustment, and wishesto register or record the place at which this adjustment was made, hemerely depresses the tab 102 which will cause the registering lever 101to rotate about the pivot 103 and the teeth of the lever 101 will engagethe teeth of the detent gear 90.

The detent lever 101 has a key-hole shaped slot 104. A spring-loadedbutton 105 (FIG. 18) has a smaller cylindrical section 106 correspondingto the narrow portion of the slot 104 and a larger circular section 107which corresponds to the larger diameter section of the slot 104.Therefore, with the lever 161 in its dotted line position, the button105 will be located within the narrow end of the slot 104 with the largediameter portion 1117 held beneath the surface of the lever 1111 (asshown in FIG. 18). A spring 109 normally maintains the lever 101 in thedotted line position with the tab 102 protruding from the centralsupport. When however, the user wishes to move the detent lever 101 intoengagement with the detent gear 91), he may push the tab 162 and thelever 101 will be moved into its solid line position. The button 1115will also be moved to the lower end of the slot 104 and due to spring110, the portion 107 of the button will be forced into the largerdiameter section of the slot 1%, thereby holding the registering lever101 in engagement with the gear 90.

However, the user may, notwithstanding the positioning of the nose 100within the detent 92, rotate the focus wheel 66 to force the slide 96and the nose 101) to move against the spring 98. The nose 101 will thenagain travel around the periphery of the disc 91. If the nose is movedclockwise about the disc 91, which is in the direction of short rangefocus adjustment, the nose 100 will not there-after drop into the detent92 after 360 of travel because the nose 1% will also travel around thefollower disc 93 and against the arm 94 thereof. The latter will stop byabutment against stop 90 since that portion of the follower disc 93adjacent arm 94 has a radius equal to the radius of the disc 91, thefollower disc will in effect prevent the nose 101) from dropping intothe detent 92. However, when the nose is moved counter-clock- Wiserelative to the disc 91 or in a direction back toward long-range focusadjustment, the nose 100 will drop into the detent 92 upon coming to aposition adjacent to the detent, which will serve as an indication tothe user that he has arrived at the long range focus position.

Assembly and mounting of the optical elements As illustrated, in FIGS. 3and 8 the lenses of the ocular lens unit 16 are cut segmen-tally exceptfor the eyepiece lens 16. The same applies to the spacers 115, 115between the individual lenses. The ocular lens unit is mounted in ahousing 17 which has a bevelled recess boarded by surfaces 117, 118.Surface 118 proceeds into the plane of the drawing at a 45 angle (FIG.8) and serves as a bearing surface for the base (hypotenuse) of prism 52(FIG. 12). In addition rectangular aperture stops 119, 121 are providedfor image field limitation of the ocular lens unit and prism 52 at theend of the housing 17.

During assembly of the component parts thus far described, the prism 52,the individual lenses of the ocular lens unit together with the spacers115, 115' are placed into the housing 42 with an additional spacingmember 121 which abuts the circular eyepiece lens 16. The circu'lar eyelens 16 is forced into a position of engagement with the spacing member121 and the spacer 115 by a threaded cylindrical collar 122. The latteris appropriately recessed at 123 to receive a portion of the lens 16 andthreadably engages the housing 17. The latter is secured adjustably tothe body of the lens casing (FIGS. and by screws 17 (not shown).

The prism 53 is locked against rotation by providing the mount 58therefore with a guide groove 124 paralleling the optical axis asindicated in FIGS. 12 and 15. The mount 58 is engaged by a finger 125which blocks the mount 58 against rotation. The finger 125 is formed asan eccentric extension of stud 126 so that rotation of stud 126 foradjustment pumoses allows the mount 58 :to turn to an extent about theoptical axis. The stud 126 is itself secured against further turning,after adjustment, by rotation of a set screw 127.

As mentioned, light is received from an objective lens 50 by a [mirror51. The minor is inclined with respect to the incident light at an angleof 45 and is adjustable with respect thereto. The mirror is secured in amount 128 which in turn is secured to a resilient or spring-like member129 secured to a base plate 130. Provided in the base plate 130 are twoset screws 131 in suitably threaded bores serving as an abutment for themember 129. Hence, adjusting the set screws 131 will result in aperpendicular adjustment of the mirror 51, to the light path. Alsoprovided in the frame 42 are openings 132 to render the screws 131accessible from without.

Moreover, base plate 130 is secured rotatably to the frame 42 by ashoulder screw 133. The side of base plate 131) further is engaged bytwo set screws 134, 134' to fix the base plate in a given position ofrotation about a circular extension on the frame 42. Thus, an adjustmentof these screws 134, 134' will result in rotating the M1111- ror aboutthe axis of screw 133. By the foregoing adjustments, the mirror can beadjusted in two planes independently.

For purposes of mounting the objective lens unit 16, the unit is heldwithin the lens mount 55 within a bore which at its rear end has a stop135 for the objective lens mount. The objective lenses are held by themount 55 attached to housing 42, and a closing frame 136 which isscrewed onto the mount 55. At the same time, the frame 136 serves as aguide rail for the objective shutter.

It will be understood that the foregoing description relates to aparticular embodiment and is therefore merely representative.Consequently, changes (may be made therefrom without departing from theteachings of the invention. In order fully to appreciate the spirit andscope of the invention, reference should be made to the appended claimsin which:

We claim:

1. A focusing mechanism for a binocular telescope comprising a rotatablefocusing wheel, a drive shaft connected to said wheel, said drive shaftbeing adapted to actuate a mechanism for adjusting the position of oneof the optical elements of a lens system, a detent gear having teethabout the periphery thereof and being freely mounted for rotation aboutsaid drive shaft, a generally circular detent disc carried by saiddetent gear, said disc having a recess in a portion of its periphery, aslide rotatably carried by said drive shaft and means permitting limitedradial movement of said slide, said slide having a nose portion engagingperipheral portions of said disc, resilient means for urging said noseportion into said recess, a registering lever pivotally mounted andfixed relative to said drive shaft defining teeth engageable by theteeth of said detent gear, and rneans externally operable of saidbinocular to move the registering lever into engagement with said detentgear to fix the position of said recess.

2. A focusing mechanism for a binocular telescope comprising a rotablefocusing wheel, a drive shaft connected to said wheel, said drive shaftbeing adapted to actuate a mechanism for adjusting the position of oneof the optical elements of a lens system, a detent gear having teethabout the periphery thereof and being freely mounted for rotation aboutsaid drive shaft, a generally circular detent disc carried by saiddetent gear, said disc having a recess in a portion of its periphery, aslide rotatably carried by said drive shaft and means permitting limitedradial movement of said slide, said slide having a nose portion engagingperipheral portions of "said disc, reslient means for urging said noseportion into the detent recess, a registering lever pivotally mountedand fixed relative to said drive shaft defining teeth engageable by theteeth of said detent gear, and means operable externally of saidbinocular to move the registering lever into engagement with said detentgear to fix the position of said recess, said registering lever beingspring mounted to be urged normally out of engagement with said detentgear, locking means maintaining said registering lever in engagementwith said detent gear and externally operable means for releasing saidregistering lever, a follower disc mounted for free rotation about thedrive shaft against the detent disc, said follower risc having aperipheral Iar-cuate portion conforming to the curvature of said detentdisc and a sector of lesser radius adapted to uncover portions of thedetent disc including the recess therein, a stop arm attached to saidfollower disc intermediate said arcuate portion and sector and extendingradially beyond the edge of the detent disc, such that when the noseportion of the slide is moved about the periphery of the detent disc inone direction, it engages the follower arm and the arcuate portion ofthe follower arm prevents the nose portion from entering the recess inthe detent disc upon rotation of the follower arm past the recess.

3. A focusing mechanism for a binocular telesgope comprising a rotatablefocusing Wheel, a drive shaft connected to rotate with said Wheel, saiddrive shaft being adapted to actuate a mechanism for adjusting theposition of one of the optical elements of a lens system, a springbiased element rotatably carried by said drive shaft, a member freelyrotatable about said drive shaft, said member having a radially disposeddetent recess, said spring biased element resiliently and detachab lyengag-able to said rotatable member as said spring-biased element isurged into said detent, externally operable means for detac'h ableengagement with said rotatable member to temporarily restrain rotationthereof thus to index an angular position of said detent relative to aselected optical adjustment, said spring element further disengagablefrom said rotatable member during continued rotation of said shaft, saidshaft further rotatable to return to said indexed adjustment.

4. In a binocular telescope including optical elements of a lens systemmounted on a frame, a focusing mechanism comprising anexternally-operable wheel, a drive shaft connected to said wheel, saiddrive shaft being adapted to actuate a mechanism for adjusting theposition of one of said optical elements, an indexing rnember freelymounted for rotation about said drive shaft, said member defining aradially disposed detent recess, externally-operab le means for fixingsaid indexing anember at any angular position with respect to saidframe, a spring-biased slide rotatably carried by said drive shaft, saidslide having a nose portion urged by said spring into said detent recessto detaohably engage and index said shaft with said angularlypositionable indexing member.

References Cited by the Examiner UNITED STATES PATENTS 1,873,571 8/1932Fried; 3s2 140 2,294,250 8/1942 Sperry 355 172 2,487,308 11/1949Oastedello -46 FOREIGN PATENTS 143,394 8/1903 Germany.

DAVID H. RUBIN, Primary Examiner.

JEWELL H. PEDERSEN, Examiner.

L. ORLOFF, J. G. BOLTEN, Assistant Examiners.

3. A FOCUSING MECHANISM FOR A BINOCULAR TELESCOPE COMPRISING A ROTATABLEFOCUSING WHEEL, A DRIVE SHAFT CONNECTED TO ROTATE WITH SAID WHEEL, SAIDDRIVE SHAFT BEING ADAPTED TO ACTUATE A MECHANISM FOR ADJUSTING THEPOSITION OF ONE OF THE OPTICAL ELEMENTS OF A LENS SYSTEM, A SPRINGBIASEDELEMENT ROTATABLY CARRIED BY SAID DRIVE SHAFT, A MEMBER FREELY ROTATABLEABOUT SAID DRIVE SHAFT, SAID MEMBER HAVING A RADIALLY DISPOSED DETENTRECESS, SAID SPRING BIASED ELEMENT RESILIENTLY AND DETACHABLY ENGAGABLETO SAID ROTATABLE MEMBER AS SAID SPRING-BIASED ELEMENT IS URGED INTOSAID DETENT, EXTERNALLY OPERABLE MEANS FOR DETACHABLE ENGAGEMENT WITHSAID ROTATABLE MEMBER TO TEMPORARILY RESTRAIN ROTATION THEREOF THUS TOINDEX AN ANGULAR POSITION OF SAID DETENT RELATIVE TO A SELECTED OPTICALADJUSTMENT, SAID SPRING ELEMENT FURTHER DISENGAGABLE FROM SAID ROTATABLEMEMBER DURING CONTINUED ROTATION OF SAID SHAFT, SAID SHAFT FURTHERROTATABLE TO RETURN TO SAID INDEXED ADJUSTMENT.